Discriminated approach-avoidance task--a new paradigm for measuring both appetitive and aversive memory processes...

Research on mnemonic processes in rats has predominantly made use of either appetitively or aversively motivated tasks. These behavioral paradigms are popular because rats are easily trained and a range of stimuli and response alternatives are available. Also, these paradigms have been generally found to be sensitive to pre- and post-trial manipulations with a variety of drugs having hypo- and hypermnesic effects. However, the available procedures do not permit a qualitative analysis of the memory changes, namely, a dissociation between the effect of a compound under study on the memory for pleasant versus unpleasant events, under the same experimental conditions. The discriminated approach-avoidance paradigm presented here is a novel method that enables this to be investigated quite easily, in rats. This behavioral paradigm was developed originally to assess the retrieval bias in the learned helplessness condition, and subsequently has been employed in studies of the pharmacological effects of several stress-related neuropeptides on appetitive and aversive memory processes.